[code-reflection] RFR: Support storing the code that builds the code model [v18]

[Maurizio Cimadamore]

On Wed, 12 Mar 2025 18:00:05 GMT, Mourad Abbay <mabbay at openjdk.org> wrote:

>> In this PR we allow the user to decide how to store the code model. The first option is `TEXT`, if this is selected, we store the textual representation of the code model. The second option is `CODE_BUILDR`, if this is selected, we store the code that builds the code model. All work done here is around the second option, because the first option is already supported.
>
> Mourad Abbay has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 20 additional commits since the last revision:
> 
>  - Merge branch 'code-reflection' into code-model-storage-option
>  - Load OpFactory and TypeElementFactory before invocation of opMethod only if the opMethod has there params.
>  - Fix the remaining compiler tests failures
>  - Fix some of the test failures (3 remains)
>  - Fix the remaining test failures of SwitchExpressionTest2
>  - Fix almost all test failures of SwitchExpressionTest2 (one remaining)
>  - Pass arrayType instead of eleType in OpBuilder.buildArray
>  - Ensure that block params are inserted in the correct order
>  - Add missing imports
>  - Merge branch 'code-reflection' into code-model-storage-option
>  - ... and 10 more: https://git.openjdk.org/babylon/compare/1fa13c4a...966005ce

src/jdk.incubator.code/share/classes/jdk/incubator/code/internal/CodeModelToAST.java line 239:

> 237:     }
> 238: 
> 239:     public static CoreOp.FuncOp addVarsWhenNecessary(CoreOp.FuncOp funcOp) {

Maybe I'm missing something obvious. But if you have something like:

func @"f" ()java.util.Map -> {
    %0 : java.util.Map<java.lang.Integer, java.lang.Integer> = new @"func<java.util.HashMap>";
    %1 : int = constant @"1";
    %2 : int = constant @"2";
    %3 : java.lang.Object = invoke %0 %1 %2 @"java.util.Map::put(java.lang.Object, java.lang.Object)java.lang.Object";
    return %0;
}


Can't we translate as:


Map $0 = new HashMap();
int $1 = 1;
int $2 = 3;    
Object $3 = $0.put($1, $2);
return $0;


Note how this translation is very 1-1 and direct, and doesn't require any adaptation step in the model. We just emit a new local variable for each op we see in the body -- and then refer to operands via their corresponding (locally declared) variable.

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PR Review Comment: https://git.openjdk.org/babylon/pull/305#discussion_r1993725923